The method of sinus node-like pacemaker cells from human induced pluripotent stem cells by BMP and Wnt signaling

Exogenous Maresin1 attenuates doxorubicin-induced cardiomyocyte ferroptosis and mitochondrial impairment via NRF2/GPX4 axis

Doxorubicin (Dox)-induced cardiotoxicity in patients with cancer, mediated primarily through cardiomyocyte ferroptosis and mitochondrial dysfunction, presents both life-threatening risks and significant limitations to Dox chemotherapeutic efficacy. The study investigated the therapeutic potential and mechanistic role of Maresin1-a novel proinflammatory regression mediator (SPM) -in Dox-induced cardiomyocyte ferroptosis. We employed both in vitro and in vivo models: H9C2 cells and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) for in vitro ferroptosis modeling and C57BL/6 mice for in vivo validation. Our key findings showed that Maresin1 in Dox-treated cardiomyocytes attenuated lipid peroxidation, upregulated the anti-ferroptosis-related protein expression via the NRF2/GPX4 axis and mitigated mitochondrial structural and functional impairment. However, inhibition of NRF2 signaling abolished the cardioprotective effects of Maresin1 against Dox-induced ferroptosis. In conclusion, Maresin1 preserved cardiac function by preventing Dox-associated cardiomyocyte ferroptosis and mitochondrial impairment through the NRF2/GPX4 axis activation.

Evaluation of the Potential Targets of Shenxian-Shengmai Oral Liquid in Treating Sick Sinus Syndrome Based on Network Pharmacology and Molecular Docking

Shenxian-Shengmai (SXSM) is a Chinese patent medicine used in the treatment of sick sinus syndrome (SSS). However, its active chemical compounds and the underlying molecular mechanisms remain unclear. In this study, we researched the underlying mechanisms of SXSM in treating SSS. We conducted network analysis and molecular docking to identify the small molecules and core targets responsible for the therapeutic efficacy of SXSM on SSS. In vitro experiments were performed to verify the potential therapeutic mechanism. Network pharmacological analysis identified 17 core targets. Among these, BMP4, KCNH2, KCNMA1, and KCNQ1 were identified to be involved in various biological processes, such as the formation and regulation of the cardiac pacemaking system and potassium ion transmembrane transport. The experimental analysis revealed that SXSM could upregulate the expression of the Bmp4/Tbx3/Hcn4 pathway and the expression of Kcnh2, Kcnma1, and Kcnq1 channels, which protected and improved the pacemaking function of pacemaker cells (P cells) and increased the heart rate. These findings provide a scientific basis in the study of the mechanism of traditional Chinese medicine in the treatment of SSS.

Cadherin-5 facilitated the differentiation of human induced pluripotent stem cells into sinoatrial node-like pacemaker cells by regulating β-catenin

Our study was conducted to investigate whether cadherin-5 (CDH5), a vascular endothelial cell adhesion glycoprotein, could facilitate the differentiation of human induced pluripotent stem cells (hiPSCs) into sinoatrial node-like pacemaker cells (SANLPCs), following previous findings of silk-fibroin hydrogel-induced direct conversion of quiescent cardiomyocytes into pacemaker cells in rats through the activation of CDH5. In this study, the differentiating hiPSCs were treated with CDH5 (40 ng/mL) between Day 5 and 7 during cardiomyocytes differentiation. The findings in the present study demonstrated that CDH5 stimulated the expression of pacemaker-specific markers while suppressing markers associated with working cardiomyocytes, resulting in an increased proportion of SANLPCs among hiPSCs-derived cardiomyocytes (hiPSC-CMs) population. Moreover, CDH5 induced typical electrophysiological characteristics resembling cardiac pacemaker cells in hiPSC-CMs. Further mechanistic investigations revealed that the enriched differentiation of hiPSCs into SANLPCs induced by CDH5 was partially reversed by iCRT14, an inhibitor of β-catenin. Therefore, based on the aforementioned findings, it could be inferred that the regulation of β-catenin by CDH5 played a crucial role in promoting the enriched differentiation of hiPSCs into SANLPCs, which presents a novel avenue for the construction of biological pacemakers in forthcoming research.

Efficient generation of TBX3+ atrioventricular conduction-like cardiomyocytes from human pluripotent stem cells

Atrioventricular conduction cardiomyocytes (AVCCs) regulate the rate and rhythm of heart contractions. Dysfunction due to aging or disease can cause atrioventricular (AV) block, interrupting electrical impulses from the atria to the ventricles. Generation of functional atrioventricular conduction like cardiomyocytes (AVCLCs) from human pluripotent stem cells (hPSCs) provides a promising approach to repair damaged atrioventricular conduction tissue by cell transplantation. In this study, we put forward the generation of AVCLCs from hPSCs by stage-specific manipulation of the retinoic acid (RA), WNT, and bone morphogenetic protein (BMP) signaling pathways. These cells express AVCC-specific markers, including the transcription factors TBX3, MSX2 and NKX2.5, display functional electrophysiological characteristics and present low conduction velocity (0.07 ± 0.02 m/s). Our findings provide new insights into the understanding of the development of the atrioventricular conduction system and propose a strategy for the treatment of severe atrioventricular conduction block by cell transplantation in future.